The XRD application support cement is part of Malvern Panalytical’s solution for the automated quantitative phase analysis of all types of (blended) cements, its raw materials and intermediate products such as clinker and hotmeal. Once set-up there is no user interaction required and the analyses are performed fully automatically. The methods are based on direct phase probing with X-ray diffraction (XRD) and phase analysis with Malvern Panalytical’s HighScore Plus and/or RoboRiet software.
Malvern Panalytical supports mineralogical quantification methods for every type of material that is typical in the cement making process. These materials range from raw materials, intermediate compounds like hotmeal or clinker, and every type of (blended) cement. The control files for quantification contain the typical clinker and cement phases. The lists of phases are based on the EN 197-1, ASTM C150, ASTM C595 and ASTM C1157 classification norms. Additional compounds of interest can be selected on demand and Malvern Panalytical will then provide methods for the phase quantification of the chosen compounds.
The methods run with Malvern Panalytical’s HighScore Plus or RoboRiet software. The methods yield phase quantification results using Rietveld and/or Partial Least Squares Regression analyses. The results are in absolute wt-% and are written to exportable and customizable outputs compatible with Excel and most common LIMS systems. In addition, statistical analyses can be performed with a clustering technique allowing pass/fail or classification analyses.
Quantification accuracy with XRD may be influenced by the stability of the phase, sensitivity of the phase to sample preparation (grinding in particular) and significant changes in mineralogy of the additives. For this reason, Malvern Panalytical only guarantees repeatability targets for the analytical precision of the methods.
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The XRD application support cement is part of Malvern Panalytical’s solution for the automated quantitative phase analysis of all types of (blended) cements, its raw materials and intermediate products such as clinker and hotmeal. Once set-up there is no user interaction required and the analyses are performed fully automatically. The methods are based on direct phase probing with X-ray diffraction (XRD) and phase analysis with Malvern Panalytical’s HighScore Plus and/or RoboRiet software.
Malvern Panalytical supports mineralogical quantification methods for every type of material that is typical in the cement making process. These materials range from raw materials, intermediate compounds like hotmeal or clinker, and every type of (blended) cement. The control files for quantification contain the typical clinker and cement phases. The lists of phases are based on the EN 197-1, ASTM C150, ASTM C595 and ASTM C1157 classification norms. Additional compounds of interest can be selected on demand and Malvern Panalytical will then provide methods for the phase quantification of the chosen compounds.
The methods run with Malvern Panalytical’s HighScore Plus or RoboRiet software. The methods yield phase quantification results using Rietveld and/or Partial Least Squares Regression analyses. The results are in absolute wt-% and are written to exportable and customizable outputs compatible with Excel and most common LIMS systems. In addition, statistical analyses can be performed with a clustering technique allowing pass/fail or classification analyses.
Quantification accuracy with XRD may be influenced by the stability of the phase, sensitivity of the phase to sample preparation (grinding in particular) and significant changes in mineralogy of the additives. For this reason, Malvern Panalytical only guarantees repeatability targets for the analytical precision of the methods.
The analytical accuracy of Malvern Panalytical’s Aeris Cement Edition (600 and 300 Watt) XRD instruments is guaranteed using Si reference samples. The instrument tests are performed at the factory, during on-site installation and/or during maintenance.
At the heart of the analysis part of the methods are Malvern Panalytical’s HighScore Plus or RoboRiet software packages.
HighScore Plus is the most advanced software suite to provide complete information on the sample and the underlying processes using qualitative, quantitative and statistical analysis on XRD data. For quantitative analysis it uses advanced methods like Rietveld and Partial Least Squares Regression (PLSR), while for statistical analysis it uses an integrated module called cluster analysis.
RoboRiet from Malvern Panalytical is a special ‘execution-only’ implementation of the Rietveld method for crystalline and amorphous phase quantification. It is designed for ‘push-button’ operation at production sites with minimal installation requirements. The RoboRiet program for automatic quantification is pre-installed on the Aeris Cement Edition systems.
The accuracy of quantification methods depends on a number of factors. One of the main factors is sample preparation. Overgrinding can destroy the crystals in a given phase and render them partially amorphous (1). This is particularly true for ‘soft’ phases like free lime, calcite and the sulphates (gypsum, bassanite and anhydrite). The best results are obtained with full XRD and XRF analyses and sample preparation methods, optimized for each technique individually. In practice sample preparation is optimized to serve both XRD and XRF. Ideally, the XRD sample should be ground at lower rpm and shorter time compared to XRF. If available at customer site, we recommend that the result is crosschecked with other techniques such as titration and DSC/TG. This crosscheck only needs to be done once at the outset or subsequently whenever the sample preparation strategy or equipment is changed. Further, it is important for any process control application that the sample preparation is reproducible.
Another factor that is important to consider is the number of sources of additives like fly-ash, slag and pozzolan. Additives coming from different sources have different characteristics in their diffraction signal. Applying a method for an additive coming from one source to an additive coming from another source may render the results inaccurate.
The last factor that is of importance is the hydration of free lime. Free lime converts to portlandite when exposed to moisture. It is thus recommended that samples be measured immediately after preparation without any delay. If this conversion inadvertently happens, XRD will underreport the free lime content.
Malvern Panalytical guarantees the performance of the methods by specifying the repeatability targets. Reproducibility is not taken into account as it highly depends on the quality of the sample preparation. Typical repeatability values are listed in Table 1. The repeatability tests are performed by applying the methods on the same sample at least 10 times. Values for the repeatability of each phase are given in 1σ. Following (2), 1σ guarantees that 68.3% of the measurements are within the specified repeatability.
Repeatability measurements require a good scan quality. Typical measurement conditions at the Aeris are for clinker a range 10 - 65°ϑ in 5:30 min, for cements a range 10 - 65°ϑ in 10:00 min and for raw materials a range 8 - 65°ϑ in 5:45 min for the Aeris Cement Edition equipped with 600 Watt X-ray generator. With a 300 W generator, the measurement times must be doubled. Generally, longer measurement times improve the repeatability.
The most intense peak should have an intensity of at least around 10.000 counts. For lower intensities the measurement time should be increased. The scan should not show very strong preferred orientation effects. The sample surface must be at the same height as the metal ring surface. The refined value for the sample displacement must be lower than 0.15 mm. Too energetic milling conditions are indicated by a peak broadening (larger W parameter determined by Rietveld refinement). The W parameter for alite (C3S) should not be larger than 0.025.
A good sample preparation is also required for raw materials. Minerals like gypsum, hemihydrate, anhydrite or calcite are very sensitive to preparation conditions. Too weak milling result in bad particle statistics with strong preferred orientation effects. Too energetic milling destroys the minerals and produces amorphous material. Both have a negative influence on repeatability values.
For more information see the “Aeris Cement Edition sample preparation: Standard Operating Procedure”. An improper sample preparation can affect the repeatability targets in Table 1.
Clinker
| CEM I | CEM-II/A-L | Slag cement
| Limestone, Rawmix3) | Gypsum | |
|---|---|---|---|---|---|---|
| Alite C3S | 0.4 / 0.2 | 0.4 | 0.4 | 0.4 | ||
| Alite M1 | 1.6 / 1.6 | |||||
| Alite M3 | 1.6 / 1.6 | |||||
| Belite C2S | 0.4 / 0.2 | 0.3 | 0.3 | 0.4 | ||
| Belite β | 0.4 / 0.2 | 0.3 | 0.3 | |||
| Belite α | 0.2 / 0.1 | 0.1 | 0.1 | |||
| Belite γ | 0.2 / 0.1 | 0.1 | 0.1 | |||
| Ferrite | 0.2 / 0.1 | 0.2 | 0.2 | 0.2 | ||
| Aluminate cub. | 0.2 / 0.1 | 0.2 | 0.2 | 0.2 | ||
| Aluminate ortho | 0.2 / 0.1 | 0.2 | 0.2 | 0.2 | ||
| Free Lime | 0.1 | 0.1 | 0.1 | 0.1 | ||
| Portlandite | 0.1 | 0.1 | 0.1 | 0.1 | ||
| Periclase | 0.1 | 0.1 | 0.1 | 0.1 | ||
| Arcanite | 0.1 | 0.1 | 0.1 | 0.1 | ||
| Aphthitalite | 0.1 | 0.1 | 0.1 | 0.1 | ||
| Calciolangbeinite | 0.1 | 0.1 | 0.1 | 0.1 | ||
| Gypsum | 0.2 | 0.2 | 0.2 | 0.2 | ||
| Hemihydrate | 0.2 | 0.2 | 0.2 | 0.2 | ||
| Anhydrite | 0.2 | 0.2 | 0.2 | 0.2 | ||
| Calcite | 0.2 | 0.2 | 0.2 | 0.2 | 0.2 | |
| Quartz | 0.1 | 0.1 | 0.1 | 0.1 | 0.1 | |
| Dolomite | 0.1 | 0.1 | ||||
| Mica | 0.1 | 0.1 | ||||
| Hematite | 0.1 | |||||
| Plagioclase | 0.1 | |||||
| Orthoclase | 0.1 | |||||
| Slag | 0.7 / 0.4 |
The Aeris Cement Edition is supplied with a pre-installed set of files for automatic quantification: clinker, CEM-I, limestone-cement, gypsum, limestone, rawmeal and hotmeal (XRD Cement Solutions Basic Pack, 9430 020 81001). The files are designed for an optimized sample preparation (automatic swing-disk mill, 750 rpm, 30 sec milling, 100 kN pressing in steel rings for 30 sec). For more details see the “Aeris Cement sample preparation: Standard Operating Procedure”. A different sample preparation, especially if a sample should be used both for XRF and XRD, requires a fine-tuning of the files. Additional phases can be included in the files upon request.
Quantification files for additional materials like slag cements, fly-ash cements, other blended cements, pure slag, pure fly-ash, other raw materials can be ordered in the Premium Pack (9430 020 81011).
Output of the results is in a pie chart on the AERIS touch screen and in a TXT file on the system, which can be exported. Additional output options are the data transfer to a LIMS in file format compatible with FLSmidth and Thyssen-Krupp Industrial Solutions (Polysius) based automation and a table in Excel file format to a separate computer or network. Other file formats must be ordered separately.
The accuracy of the pre-installed CEM-I file is demonstrated by measurement and quantification of the VDZ100 standard sample of the organization of the German Cement Industry, VDZ (Table 2).
| Reference from VDZ100 | Aeris measurement Value (std. dev.) | |
|---|---|---|
| Alite | 59 ±0.6 | 59.20 (0.08) |
| Alite M3 | 23.14 (0.63) | |
| Alite M1 | 36.06 (0.60) | |
| Belite sum | 14.1 ±0.5 | 14.06 (0.07) |
| Belite beta | 13.49 (0.07) | |
| Belite alpha | 0.26 (0.01) | |
| Belite gamma | 0.31 (0.01) | |
| Ferrite | 6.9 ±0.5 | 6.66 (0.05) |
| C3A sum | 8.3 ±0.3 | 8.47 (0.03) |
| C3A cubic | 5.9 ±0.3 | 6.03 (0.04) |
| C3A ortho. | 2.3 ±0.3 | 2.44 (0.03) |
| Free Lime | 0.3 ±0.1 | 0.15 (0.02) |
| Portlandite | 2.0 ±0.3 | 1.72 (0.02) |
| Periclase | 0.1 ±0.1 | 0.12 (0.03) |
| Arcanite | 0.3 ±0.1 | 0.20 (0.04) |
| Aphthitalite | 0.2 ±0.1 | 0.17 (0.03) |
| Calciolangbeinite | b.d.l. | |
| Gypsum | 0.2 ±0.1 | 0.32 (0.04) |
| Bassanite | 1.8 ±0.3 | 1.64 (0.05) |
| Anhydrite | 2.6 ±0.3 | 2.69 (0.03) |
| Calcite | 4.4 ±0.4 | 4.50 (0.07) |
| Quartz | 0.2 ±0.1 | 0.11 (0.03) |
(1) Witzke, T. & Füllmann, T. (2015): Influence of sample preparation of clinker on Rietveld quantification results and crystallite size. IBAUSIL, 16th-18th September, Weimar, Volume 1, 465-472
(2) Wheeler, D.J. and Chambers, D.S. Understanding Statistical Process Control. s.l. : SPC Press, 1992.
Second Edition, 2020
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